Expression analysis and functional characterization of a pathogen-induced thaumatin-like gene in wheat conferring enhanced resistance to Puccinia triticina

Pathogenesis-related (PR) protein-5, is involved in host defense system against both biotic and abiotic stresses as well as the regulation of physiological processes in numerous plant species. Our earlier studies have reported the isolation of a full-length TaLr19TLP1 gene (516 bp, GenBank accession No. KJ764822) from wheat infected by leaf rust. Quantitative real-time polymerase chain reaction analyses revealed that TaLr19TLP1 transcript was significantly induced and upregulated during incompatible interaction, while a relatively low level of the transcript was detected during compatible interaction. In the current study, we demonstrate that the accumulation of TaLr19TLP1 transcript is significantly different in tested wheat organs. TaLr19TLP1 was induced by salicylic acid (SA), methyl jasmonic (MeJA), ethephon (ETH) and abscisic acid (ABA). The transcripts of TaLr19TLP1 accumulated at higher levels following pretreatment with SA, MeJA and ABA prior to infection with P. triticina. A slight induction was observed in ETH pretreated seedlings compared with the treatment without inoculation. In addition, TaLr19TLP1 was found to be predominately localized to extracellular spaces of onion epidermal cell. Knocking down the expression of TaLr19TLP1 through virus-induced gene silencing reduced wheat resistance against leaf rust pathogen. These results suggested that TaLr19TLP1 mediated disease resistance in wheat exposed to leaf rust pathogen.